Coroneal endothelial cells in man decrease in numbers with age and are not replaced following injury. If the injury is severe, or if subsequent stress occurs, corneal edema and loss of transparency may occur. Because little is known about endothelial regeneration, the overall objectives of our studies are: 1) to compare the effects of drugs, irrigating solutions, inflammation, and increased intraocular pressure on the ultrastructure and function of regenerated and normal endothelium; 2) to determine effects of Vitamin A, thyroid hormones, and insulin on corneal regeneration; and 3) to characterize the metabolic changes in regenerated and cultured endothelium.